Lehrs for glassware



May 2, 1961 AA LAWSON 2,982,052

LEI-IRS FOR GLASSWARE Filed Jan. 6, 1956 4 Sheets-Sheet 1 IAN jh. s i 1:0 fnl O E.. mMJlmO k dur a. @W5 H To jun@ nmw m0 1| m HHHH -VVnnnnnnnnnnn n unzun ugw L F .1S \\\,z\// M ....1 1\ a w wm MM S KH a May2, 1951 A. LAwsoN 2,982,052

LEHRS FOR GLASSWARE Filed Jan. 6, 1956 4 Sheets-Sheet 2 @Ma/ww `A`3 May2, 196g; A` LAWSON LEHRs FOR GLAsswARE 4 Sheets-Sheet 3 Filed Jan. 6,1956 May 2, 1961 A. LAWSON 2,982,052

LEI-IRS FOR GLASSWARE Filed Jan. e, 1956 4 sheets-sheet 4 INVENTOR. ZwXM@ @Mam/x A TTORNE YJ `f1@surrounding'arectangular passageor A b y inglongitudinally throug'hthe lehr-` for the rfulfle'ngth' thereof,Vthechanber being rectangular incross-section. jendless 'AzconveyorfA offopenwork i'naterial,`Tv such as United States PatentfO z,9`s2,0sz`LEHRs FoR GLAsswARE `A lec Lawson, Wembley, England, assignor toBritish Hartford-Fairmont Limited, Greenford, England, a British companyFiled `lan. 6, 1956, Ser.` No. 557,807

priority, application Great Britain July 28, 1955 12 claims. (ci.45t-47) 'This invention relates tolehrs for glasswareand, in particular,to decorating lehrs for treating glassware on which decorative matter ofa ceramic nature in a vapourisable vehicle, such as wax, has ,beenplaced, the treatment being such that the decorating matter on theglassware is rst heated to drive oil the vehicle, the ceramic decorativematter then being fused or matured. Thereafter the decorated ware isannealed, or re-annealed in the lehr. t According to the invention thereis provided a lehr for glassware on which ceramic decorative matter in avapourisable vehicle has been placed, comprising means for conveying theware through the lehr, means for heatf ingthe ware during the first partAof its journey through the 1e`hrmeansfor introducing air into the lehrat about a first zone in which the said vehicle vapourises, means forpreheating said air. to a temperature substantially equal to, or greaterthan, the temperature in saidA lirst zone, means for venting theintroduced air which carries with it the vapours resulting from thevapourisation of said vehicle, means for introducing further` air intothelehr at about a second zone in which carbonaceous material derivedfromv said vehicle will burn, means for preheating said further air to atemperature substantially equal to, or greater than, the temperature'insaid second zone, and means for venting the introduced further airwhich carries with 'itgases resulting from the combustion of saidcarbonaceous material. Y ForA a better understanding of the invention,and to show how the same may be carried into eifect,'reference will nowbe made to the accompanying drawings in which:

`Figurel showsa longitudinal vertical sectionthrough a lehr, a Figure 2shows an enlarged longitudinal verticalv section through part ofthe lehrshown in'Figure l,

Figure3 `shows a horizontal section along' the line vIlIIII of Figurel,`

vFigure4 shows a vertical sectionfalong the line of Figure 2, j f ,3 Y bVFigure '5 shows a vertical section along the line o f Figure 2,

`Figure 6 sho-ws afhorizontalf,sectionialonghe `line g Figure 7i is" aview corresponding to partoflFrigtlflf.3,2,V Y e `butshowing amodicationof thejleh ceramic nature fhas been placed.

chamber -2 extend- 2,982,052 I atented May 2, 1961 ice to the oor of thechamber, by a series of evenly spaced metallic rollers (not shown)carried in a guiding frame structuregenerally indicated at 4 in Figures4 and 5.` On leaving .the rear-lend of the passage the upper reach 3.of-'the conveyor. passes over a rearwardly extending glasswareinspection and packing table 5, toa suitable conveyor supporting anddriving Vmechanism 6 at the outer extremity of the inspection andpackingtable. The direction of the conveyor is changed by this sup-Yporting and driving mechanismand the return, or idle, reach 7 of theconveyor passes beneath, the lehr where it is supported and guided atintervals by suitable supporting'and guiding `devices 8 and 9. At thefront of the lehr, the conveyorpasses into the longitudinal chamf berorpassage 2 beneath a verticallyV adjustablefront door or closure 10'asshown in Figures 1 and 2.` This front door or closure 10 may be adjustedverticallyso that its lower edge is just high enough above the upperreach yof the conveyor to aiiordclearance for Ithe ware onr the conveyorduring any particular operation. The longitudinal chamber or passage'Zof the lehr may thus be partly closed at its-front end to prevent egressof tunnel atmosphere labove the level of the lower edge of the door 'orclosure. 10.. Y Y Y The lehr is supported above oor orground level 11,so as to provide sufficient space for the return reach 790i theconveyorand also so as to locate the upper, or ware carrying, reach 3 of theconveyor at a desiredllevel, The supporting structure employed mayconsist of a suitable supporting framework,` including upright legsorfsupportng members 12.YV jtEXcept Aas to particular features whichhereinafter will be specifically pointed'out, the construction of thewalls ,rlrwill not be` described in detail. Suitable ref racltorymaterials, insulating materials and metallic m a terials are'ernployedand relatively arranged to provide lehr walls which delinetheaforesaidchamber'or passage 2 and which are suitable forwithstanding the elevatedtemperatures necessary for the desired thermal treatment of'theglassware Athatis to be transported through the chamber. Thus, in thezones of relatively high temperature'the walls consist of refractorymaterial backed by suitable insulation. Other portions of the chamberyinwhichy the temperatures arelower, have walls of less `thickness andstill cooler portions/of thelehr havewalls `terial. Y t

The passage or chamber 2 mayconveniently be considered to comprise fourzones viz: a preheatingzone .atgv the entrance toA the lehr, .a fusingor firing lzone, an

annealing zone, ancha co o1ing,zone. The preheating zone and/the`fusingzoneareiheated *by radiant h at from electric heating elementsT 13litted Y transversely across theroof ofthelehr,Y as indicated Figur'el,and immediately beneath the upper` reach `of the. conveyor.

Vas indicated in Figures l and 5, th"e elements being spaced 16 1n thesi Qevenlyalong vthe-,pass ageway. 4 niu'ltiplicityf of lsuch t heatersis providedfand :any ysimple` selectorQswitchor switches vmay beassociated "with the elements v-so as tfoz v .perr'nit theseletionpfhigh'or low t ernperatinfe.'zones` at 4 .any part` ofthepreheating and fusing or firing zones(las,`

anxdelivering airinto a pair, of

eresmas t -3 the chamber at 16A. The circulating air fans 14 are drivenby an electric motor17, and to avoid damage to s aid motors fromconducted-or convected heat, the motor isisolated from'thefans 114 bythe use f T'a well known exibleibelt 'drive1'8 `(`see-`Figure"2).

Thefans '14idisch'arge airythroiigh' the'two discharge ducts 15,`downthetwo'side ducts 16 androut-into'the chamber at 1:6A. The airthen passesupwardly through the conveyor and -pa'st'th'e `glassware in transitthereon, to the suction port 19 of the fan. It will be readilyappreciated vthat in thecourse o'f such circulatory moveme'rithe airwillhave lfirst absorbed heatlfrorn'theY heating" elements and thendistributed-such heat evenly over that'section 'of the chamber and thevglassware in transit therein.r `By automatic thermostatic control ofthe switching Vof the elementsin the heating zone with which suchcirculating'irjcomes into contact, it will be seen that only suchelectrical current'as isneces'sary to makeup the heat lost by'saidlcirculating air to Ythe glassware, theconveyor in transit, and toconvection, need to added during 'the'circulating cycle, 'thereforegreatly -assisting the economical function `of the lehr.

-A fan V20,v located on the roof of the lehr and beyond the fans-14 inthe direction of travel of the ware, Ysupplies iirfat substantiallyatmospheric temperature and at a low pressure(e'.g. 25 Ywatergauge)"through a pipe 21 to a ilatspiral bank or series of tubes 22 madeof heat resisting metal, `or refractory material. The itubes aresituated inthe roof of the tunnel immediately after the firing 'orfusing Azoneand extend transversely Yacross the roof as Vshown inFigures 2 and 3. `In passing through the tubes 22 the air cools-'the-chamber and in so doing becomes heated so that it leaves'the tubes at ahigher temperature than that at which it entered the tubes. The heatedairv leaves the tubes through -a connection 23 4and passes along a pipe24, leadingfrom'the connection 23, down the side`wall`of'the lehr, andalong beneath the chamber y2 to two manifoldseach of which is formedwith 'aseries of discharge'p'orts V25 and 26respectively. Therlischarg'e ports'are transversely spaced across the width"ofthe-chamber, and are located below the lowerheatin`g"elements 13,the-rsts'cries f ports 25 being located just in front of theffansf1'4and theisecond 'series ofY ports 26ibein'g located'nearer toftheventrance ofthe chamber "2, `An lexhaust vent 27 is-located above 'thefirsseries rif'fpr'ts'25,'ther`e being fasimple damper'valve'281in thevent, fr 'controllingthefoutlet from the vent. 1A similar vent29,'also"cntrollblebya damper 'valve 30, is` located above thesecond'series of ports v26,a'control valve 31 being tted in the pipe 24and being arranged forproportioningthefairbetween'the two series of`ports as-required.Vv n f 'fr Y 1 ,A fan 32, locatednear thefoutleteri'dofthe lehr, supiplies air fat atmospheric temperatre for the lforcedcoolfingof the glassware, the'airpassing'through the cooling'zone andout'throughanexhaust'ventr34. "The quantity of `air -supplied by the fan32 'can'he regulated by transported through a porto'n of the lehr.

temperature of the ,decorated glassware to the decoration fusingtemperature, during which period the ware is being This period of timemay vary according to the starting temperature of the glass, the shapeand/or thickness of the walls of the glassware, or other factors whichmay he involved in the treatmehtof 'the ware.

The ceramic decorating matter is carried in a suitable Vehicle-ormediumsuch'as wax, Aand applied to the glassware before the ware isplaced in the oven. During the period in which the ware is being heatedup to the decoration fusing temperature, the readily volatile matter ofthe vehicle volatilises olf leaving the ceramic matter on the glassware,some of `vthe vehicle being carbonised in situ and remaining on the'ware 4as a carbonaceous deposit. To effect the removal of thecarbonaceous deposit it is necessary for the ware to remain in anoxidising atmosphere at atempe'rature of, say between 650 F. and 850 F.for a considerable time. The final fusing temperatureshould not be'attainedun'til such time as vthe deposit has been completely burned offthe ware. In order 'to remove'the volatiles given off Vby the vehicle onheating,jus`e is'm'ade of part of the air supplied by the'fan 20,and'heat'ed during itspassage through the tubes 22. The'said air issupplied t'o the series of discharge ports 26, which are located atabout the zone in which the vehicle'is volatilised, 'andfows upwardlypast the ware, carrying the volatiles to the fume vent 29, thetemperature in this zone rangin'gfrom 200 F. to 500 F. It is thuspossible'tb' obtain a'rapid removal of the volatiles, which wouldotherwise tend to"reduce Vthe oxidising ability'of the atmosphere inthechamber, thereby increasing ythe period within which 'complete oxidationof the 'carbonac'eos 'deposit can occur. To :effect removalof thelcarbonaceous deposit 'another partl ofthe air from the fan 20, issupplied to the series of discharge ports 25 which are locatedbefore'thefusingand tiring zone. By this meansa lconstant supply ofoxygen is provided'ata point where itis most needed and as a resultthe's'peed of transit of the glassware through the lehr may beincreased. The air is introduced into the lehr,'at eachlocation"of'introduction, at a temperature which is lsubstan-Vtiall'yiequal to, or slightlygreater than the temperature '.falcontrolvalve`33situated- ,atthe discharge side of the fan. -Y In the operationof'the '-lehr"descrihed, the'glassware,

ionwhich decoratingmatter ofa `:ceramic natuefhas been placed, iscarriedthroughthe lehr on the endless conveyor. :The Vglassware maybe at `arelatively low tempera-` 1ture, suchasjthev arnbientfair'temperature,at'the tiriieit t v'isrnrnoved into; the chamber .on the conveyor. `ItisVneces- .jsaryz'duringthe first stageof'trea'tment'ltoheat the V"wareinthe lehr fromV the .initialjrelatively'-low` temperature up "to thedesired'high temperatureat which-the decorating n i Lmaterial willfuse'ontheglass.` Thislattertemperature ay be in the order-"ofjlOOTTF,Aornjiore'faboveftheupper .annealing temperature tof, the Vware, f Le.the ,ternperatu,re vfat which strains in the glass would be '1"elie\`fed.`l lThus'the @decoration vfusing .temperature rnayjhe 11,00?to1l80- :for glass having" 'an upper'annealing-temperaturepointobtaining in the'lehr at the' location of introduction.

The ware is heatedl to( thefinal fusing temperature in the preheatingz'onean'd is uniformly heated by Athe 'air circulated bythe twofans v14.'It is well known that in similar ylehrs a'system' of circulating andreheating air is used where two or more volumes of suchheated air`aredischarged into thef'lehr tunnel in substantially opposlte rotary andtransverse directions, therebyicreating turbulence'at that part rof thetunnel chamber where the two substantially 'opposite vvolumes come intocontact with Veach other. However, the 'method of passing all the heatedair upwards and transversely through the fans eliminates anyconcentration of heat or hot spots in the chamber caused ,by saidturbulence and therefore tends to promteauniforrn temperaturethroughout'the ,zone of influence of the circulating fans.

'Asalready described,"tl1'e glassware in a' decorating lehr is raised toa temperaturein the'order of 100 F. l"aboveits upperannealinglimihandAis maintained atsuch -al temperatureforls'uch timelasis'requiredr'toffsethe decoration t`o` thefglass'ware, butfitjis'desirable to be able wto,A reduce this`.tenprature`to theupper'yannealing limit fas .quicklyaspos'sible ,after lthe vcompletion`of the necessary firing or fusingfperidd. v '1`his'fre'duc`tion 'intemperavtu'refis achieved by-meanscf heatlexchange between thehotfairninf the-.chamber and 'the cool air passingthrou'gh cools'the'sglassware :to :the fupper? annealing temperature The jheat-exch'angealso serves into .the @lehr through@ ther-'dischargev `tion in which thesaid-vehicle `vaporises, first venting 3 fme'ans `situatedf'dire`ctl`yopposite saidl firstvv manifold delvice `for vventing the introducedfirst part'ofthelainwhich carries lwith it the vapours resulting fromthe vaporisac .f5 Y ports' 25 and-26thus` obviating the necessity fortraneously preheating such air. Y The glassware then passes along thechamber and enters the'cooling zone, where the ware is cooled by the sexair supplied from the fan, the ware finally arriving at the inspectionand moved. I

VIn the lehr hereinbefore described with reference to the accompanyingdrawings the preheating zone and the fusing zone are heated byelectrical heating elements 13. However, the lehr may be heated by oilfiring, or by gas-fired radiant tubes.

In the modification of the lehr shown in Figure 7, the ,pipe-24 of thelehr shown in Figures 1 to 6 is replaced by a pipe 24A which extendsfrom the tubes 22, along the top of the lehr chamber in the fusing zoneand then down the side wall of the lehr'to the two series of discharge`ports 2S and 26. By this means the air for introduction into the lehris further preheated.

I claim:

1. A lehr for glassware on which ceramic decorative packing table 5 fromwhich it is re lmatter in a vaporisable vehicle has been placed,comprising means for conveying ware through the lehr, means for heatingthe ware in a pre-heating section of the lehr during the first part ofits journey through the lehr, means for supplying air to said sectionfrom outside it, a first manifold vdevice .extending transverse to thedirection of conveyance of the ware through the lehr for introducing afirst part of the air supplied by said air supply means from outsidesaid section into the lehr as 'a vertical curtain at about a first zoneof said section in which the said vehicle vapourises, first ventingmeans situated directly opposite said first manifold device for ventingthe introduced first part of the air which carries with it the vapoursresultmg from the vaporisation of said vehicle, a second manifold deviceextendingtransverse to the direction of conveyance of the ware throughthe lehr for introducing a second part of the air supplied by said airsupply means from outside said section into the lehr as a verticalcurtain at about` a second yzone of said section in which carbonaceousmaterial derived from said vehicle will burn, second venting meanssituated directly opposite said `second manifold devicefor venting theintroduced second part of the alr which carries with it gases resultingfrom the combustion of carbonaceous material, and means for pre-heatingsaid first and'second parts of air supplied' by the air-supply meansjbefore the airis introduced into the lehr. v 2. A lehr for glassware onwhich ceramic decorative matter in a vaporisable material has beenplaced, comprising meansfor conveying the ware through the lehr, meansfor heating the ware in a pre-heatingY section of the lehr duringy thefirst part of its journey through the "6 devices, and located in thelehr after the heating means.

3. A lehr as claimed in claim 2, wherein said lheatexchange means is abank of tubes disposed in the roof of the lehr.

4. A lehr as claimed in claim 2, wherein said heatexchange meansincludes a conduit which passes through a fusing zone of the lehr,following said pre-heating section, and serves to convey the pre-heatedair to said first and second manifold devices. Y

5. A lehr for glassware on which ceramicdecorative matter in -avaporisable vehicle has been placed, comprising means for conveying theware through the lehr, means for heating the ware in a pre-heatingsection of the lehr during the first part of its journey through thelehr, means for supplying air to said section from outside it, a rstmanifold device extending transversely across the bottom of the lehr forintroducing a first part of theY air into the lehr from outside saidsection asa first upwardly-owingvertical curtain at about a first zonein which the said vehicle vaporises, first venting means disposeddirectly above said firstrmanifold device for venting the introducedfirst part of the air which carries with it the vapours resultingfromrthe vaporisation of said vehicle, a second manifold deviceextending transversely across the bottom of the lehr for intro,

Y rectly above said secondA manifold device for venting the iehr, meansfor supplying air to said section from outv side it, a rst manifolddevice extending transverse to `the directionof conveyance of the warethrough the lehr 'supply means from `outside said section 'into the lehr"asa first Avertical curtain at about a rst zone Yof said secdtionloflsaid vehicle," a second manifold device extending Y transverse tothe direction of Aconveyance of the ware -throughthe lehrV forintroducing a second part of `thelair I supplied by-the airVsupplyineans from outside: saidfsecl'tionjinto the `lehr as a secondvertical curtain at about` Agalsecondfzoineofsaid section in whichcarbonaceous' mafiterial derived frorn'said vehicle will burn,secondventf -jng nreahns;situatedY directlyopposite said second manifold1 device for venting ,thefintroduced second 'part of the a ir i 7.`Alehr for glassware; on whichceramic decorativev .l-,f'ill'matter in avaporisable 1vehicle has been placedgncorn.-

:which earries with/it"igases resultingfrom the combustion Y introducedsecond part of the air which carries with it gases resulting from thecombustion of said carbonaceous material, and heat exchange means in thelehr for pre heating said first and second parts of the air each to arespective temperature which is not less than the temperature obtainingin the zone in which the air is to be introduced. A

6. A lehr for glassware on whichceramic decorative matter in avaporisablevehicle has been placed, comprising means for conveying warethrough the lehr, means forV heating the warerin a pre-heating sectionof the lehr during the first part of its journey through the lehr, meansfor Vsupplying air to fsaid section from outside it, a first manifolddevice extending transverse tn the direction of conveyance of the warethrough the lehr for introducing a first part of the air supplied bysaid air supplyng means fromV outside said section into the lehr as avertical curtain at about a first zone of said section in which the saidvehicle vaporises, rst venting means situated directly opposite saidfirst manifold device for venting the introduced first part of the airwhich carries with it lthe vapours resulting from the vaporisation ofsaid vehicle, a second manifold device extending transverse to thedirection of conveyance of the ware through the lehrffor introducingalsecond part of the'air supplied by saidhair supply :means from outsidesaid secton into Vthellehr as a vertical curtain at about a second zoneof said section in whichcarbonaceous material derived from said'vehiclelwill burn, second venting means situated directly opposite said secondmanifoldvdevice for venting the introduced second part of the air whichcarries with `it gases resuling 'the air-supply means before the air isintroduced into the lehr, and manually operable valve means forproportioning the pre-heated vice. Y

'prising means for,A conveying ware throughlthe lehr,

means for v4heating the ware during the first part `of,` its journeythroughgthre lehr, air-supply means, a first-manif fold deviceextendingtransverse to the directionzlqf conrei/ence earthweb thelehr.-95'- iafweveiis air-between each manifolddeasrstpart of the air;`supplied by said air supply means intof'the lehr as avertical-curtainfatabout va-first zone idwhich the'said vehicle vaporises,Airstventingfmens in association with said first manifold device forventing the introduced first partfof the air which carries with it-the'vapours resulting from the vaporisation of said vehicle, a secondmanifold device extending transverse to the direction of conveyance ofthe ware through the lehr foi introducing a second part of the airsupplied by said air supply means intoA the lehr'as a vertical curtainat about a'second zone in whichcarbonaceous material derived from saidvehicle will burn, second venting means in association with said secondmanifold device for venting the introduced second part ofthe air whichcarries with it gases resulting from the combustion of carbonaceousmaterial, means for pre-heating said first and second parts of airsupplied by the air-supply means before theV vair is introduced into thelehr, vertical ducts formed in the walls of the lehr at about a firingand fusing zone, and fanmeans associated with said ducts for causing anupward circulation of the air past the ware in a directio'n transverseto the direction of conveyance thereof through the lehr. i

8. A lehr for glassware on which ceramic decorative matter in avaporisable vehicle has been placed, comprising means for conveying warethrough the lehr, means for` heating the ware during the first part ofits journey vthrough the lehr, air-supply means, a first manifold deviceextending transverse to the direction of conveyance of the ware throughthe lehr for intro'ducing'a first part of the air supplied by said airsupply means into the lehr as aV vertical curtain at aboutA a first zonein which the said lvehicle vaporises, first venting means inassociationwith said first manifold device for venting the introduced first part ofthe air which carries with it the vapours resulting from thevaporisation of said vehicle, a second manifold device extendingtransverse to the diretion of conveyance of the ware through the lehrfor introducing a second part of the air supplied by said air supplymeans into the lehr as a vertical curtain at Vabout a'second zone inwhich carbonaceous'material derived' from Vsaid vehicle will burn,second venting means in association with said second manifold device forventing the introduced second part of the air which carries with itgases resulting 'from the combustion of carbonaceous material, meansYfor pre-heating said first and 'second parts of air supplied by theair-supply means be- Vfore the air is introduced into the lehr, fanmeans mountedjin the roof of the lehr at about a firing and fusing zone,oppositely directed ducts in the roof of vthe lehr with which ducts thefan means are associated, and vertical ducts inlthe wall ofthe lehrconnected at theirupper ends to the ducts in the roof of the lehr, andopening into the lehr at or near the bottom thereof. Y 9. A lehr forglassware on which ceramic decorative 'matter in a vaporisable vehiclehas been placed, comprising means for conveying the ware through thelehr, 'a multiplicity of electrically operable radiant heating elementslocated in the roof of the lehr and near the bottom of the lehr forheating the ware in a pre-heating section of the lehr during the firstpart of its journey "through thellehr, means for supplying air to saidvsection from outside it',` a first manifolddevice extending trans-Yverse to theV direction of conveyance of the ware through the lehr forintroducing a first p art of the air supplied f' 'by the air supplymeans from outside said section into -the lehr as a vertical curtain atabout a first zone of said section in which the said vehicle vaporises,first venting means` situated directly opposite said first manifolddehicl'e, agsecondfmanifold device extending transverse Yto thedirection of conveyance of the ware through the lehr'nttodusitlg'asswndptart of the air supplied, bythe.,

estabas vice forventi'ng theintroduced air which carries 'with it70 Vthevapours resulting from the vaporisation of said veas a vertical curtainat about the second zone of said` section in which carbonaceousmaterial'derived front si'd vehicle will burn, vsecond venting meanssituated directlyA opposite said second manifold device for venting theintroduced second part` of the air which carries with itthegasesresulting "from the combustion of said carl' bonaceous material,and cooling tubes, for pre-heating'the air,"'disposed between said airsupply means and the manifold devices, and disposed in the roof of thelehr after the heating elements.Y

10. vA lehr for glassware on which ceramic decorative matter in avaporisable vehicle has been placed, cornprising means for conveying theware through the lehr, a multiplicity of electrically operable radiantheating ele-v ments located in the roof of the lehr and near the bottoniofthe lehr for heating the Vware in a pre-heating section ofthe lehrduring the first part of its journey through the lehr, means forselectively and thermostatically controlling said elements, means forsupplying air to said section from outside it, a first manifold deviceextending transverse to the direction of conveyance of the ware throughthe lehr for introducing a firstvpart of the air supplied by the airsupply means from outside said sec,-v tion into the lehr as a verticalcurtain at about a rst zone ofsaid section in which the saidvehiclevaporises, first venting means situated d irectly opposite said firstmanifold device for venting the introduced air which carrieswith it thevapours resulting from the vaporisa- 'tion of said vehicle, a secondmanifold device extending transverse to the direction of conveyance ofthe Ware through the lehr for introducing a second part of the airsupplied by the air supply means from outside said sectiorivinto thelehr as a vertical curtain at about the second zoneA of said section inwhich carbonaceous material derivedfrom said vehicle will burn, secondventing means situated directly opposite said second manifold device forventing the introduced second part of the air which carries with it thegases resulting from the combustion of.said carbonaceous material, andcooling tubes, for pre-heating the air, disposed between said air supplymeans andthe manifold devices, and disposed in the roof of the lehrafter the heating elements.

1l. A lehr for glassware on which ceramic decorative Vmatter in avaporisable vehicle has been placed, comprising means for conveying warethrough the lehr, means for heating the ware in a pre-heating section ofthe lehr during the first part of its journey through the lehr, meansfor supplying air to said section from outsidev it, a first manifolddevice extending transverse to the -direction of conveyance ofthe warethrough the lehr for introducing a first part of the air supplied bysaid air supply means from outside said section into the lehr as avvertical curtain at 'about a first zone of said section in which thesaid vehicle vaporises, first venting means situated directly oppositesaid first manifold device for ventving the' introduced first part ofthe air which carries with it the vapours resulting from the vaporsationof said vehicle, a second'manifold device extending transverse to thedirection of conveyance of the ware through ther-lehr for introducing asecond 'part of the air supplied bysaid -air supply. means from outsidesaid section into the lehr as a vertical curtain at about a second zoneof said'section in'which carbonaceous material derived from said vehicleVwill burn, secondventing means situated directly opposite said secondmanifold devfice for venting the introduced secoudpartof the 'air whichcarries with it gases resulting from thev combustion ofcarbonaceousmaterial, means .forpreheating saidzfirst and second parts of V4airsupplied bythe air-supply means before the air is introduced into 'thelehr, a fusing or firing zone in said lehr 'following said pre-'heatingsection, an annealing'zone in said lehr follow- :"t ysubstanti'al'lyatmospheric temperature, across th'e 12. A lehr for glassware on'whichceramic decorative matter in a vaporisable vehicle has been placed,comprising means for conveying the ware through the lehr, a multiplicityof electrically operable radiant heating elements located in the roof ofthe lehr and near the bottom of the lehr for heating the ware during therst part of its journey through the lehr, means for selectively andthermostatically controlling said elements, first air supply means, afirst manifold device extending trans- -versely -across the bottom ofthe lehr for introducing a part of the air supplied by the first supplymeans into the lehr as a first upwardly-flowing vertical curtain atabout a first zone in which said vehicle vaporises, firstdamper-controlled venting means disposed above said first manifolddevice for venting the introduced first part of the air which carrieswith it the vapours resulting from the vaporisation of said vehicle, asecond manifold device extending transversely across the bottom of thelehr for introducing a second part of the air supplied by the` Vfirstair supply means into the lehr as a second upwardlyilowing verticalcurtain at about a second zone of the lehr which follows said first zoneand in which carbonaceous material derived from said vehicle will burn,second damper-controlled venting means disposed above saidsecond-manifold device for venting the introduced second part of the airwhich carries with it gases resulting from the combustion of saidcarbonaceous material, a bank of tubes interposed between said first airsupply means and said rst and second manifold devices, and located inthe roof of the lehr after, but near to the heating elements, a fusingor firing zone in said lehr following said second zone, an annealingzone in said lehr following said fusing or firing zone, a cooling zonein said lehr following said annealing zone, a conduit passing throughthe fusion the lehr at said fusingor firing zone, duct means leadingfrom said fan means tothe bottom of the lehr, said fan means beingarranged to circulate air upwardly past the ware in a directiontransverse to the direction of conveyance of the ware through the lehr,and second air supply means for passing air at substantially atmospherictemperature lacross the ware in said cooling zone so as to cool theware.

References Cited in the file of this patent UNITED STATES PATENTS1,484,116 Dressler Feb. 19, 1924 1,599,589 Richardson Sept. 14,19261,701,223 Bergman Feb. 5, 1929 1,837,311 Amsler Dec. 22, 1931 1,854,452Cramer Apr. 19, 1932 1,862,548 Prouty et al June 14, 1932 1,949,716Harsch Mar. 6, 1934 1,979,662 Bethel Nov. 6, 1934 1,982,478 Morton et alNov. 27, 1934 2,133,783 Merrill Oct. 18, 1938 2,133,784 Merrill Oct. 18,1938 2,330,984 Merrill Oct. 5, 1943 l'2,335,128 Merrill Nov. 23, 19432,458,040 Weller Ian. 4, 1949 2,660,832 Merrill Dec. 1, 1953 2,669,068Wambreuze Feb. 16, 1954 FOREIGN PATENTS 963,542 France Ian. 4, 1950

